
Stand-by
feeder
evaluation
U_STDBY_FAIL
FRQDIFF_FAIL
ANGDIFF_FAIL
FAST_READY
ANG_DIFF
FRQ_DIFF
BLOCK
U_BB_FAIL
U_BB_U_RES
DISA_INIT
TR_1_2_OK
(from Transfer direction)
TR_2_1_OK
(from Transfer direction)
U_AB_1
(from Voltage monitoring)
U_AB_2
(from Voltage monitoring)
U_AB_BB
(from Voltage monitoring)
FRQ_MEAS_1
(from Voltage monitoring)
FRQ_MEAS_2
(from Voltage monitoring)
FRQ_MEAS_BB
(from Voltage monitoring)
ANG_DIFF_1
(from Voltage monitoring)
ANG_DIFF_2
(from Voltage monitoring)
Transfer
evaluation
Fast
transfer
evaluation
ACT_LKOUT
STATUS
RST_LKOUT
GRAD_FAIL
TRANSFER_ON
NOT_READY
READY
Lockout
handling
CB_DECOUPL
(from Bus transfer)
LOCKOUT
Figure 936: Transfer readiness evaluation module diagram.
Stand-by feeder evaluation
The phase angle difference is determined between the voltage of busbar and the
voltage of the standby feeder. If phase angle difference is outside sector defined
by
Maximum phase lead and Maximum phase lag, output
ANG_DIFF_FAIL
is
activated. The measured angle difference between stand-by feeder and busbar
(ANG_DIFF) is available as function output.
Same way frequency difference is determined between the voltage of busbar and
the voltage of the stand-by feeder. If frequency difference is greater than setting
Max frequency Diff, output
FRQ_DIFF_FAIL
is activated. The measured frequency
difference (FRQ_DIFF) is shown in monitored data.
Busbar frequency gradient is also monitored and if frequency gradient is larger than
setting
Maximum DfDt, output
GRAD_FAIL
is activated.
Stand-by feeder voltage must be higher than setting
Min standby voltage. If
stand-by feeder voltage falls below the setting value, U_STDBY_FAIL is activated.
If U_STDBY_FAIL is active, then all transfers are prohibited.
Busbar voltage must be higher that setting
Min busbar voltage. If busbar voltage
falls below the setting value, U_BB_FAIL is activated. If U_BB_FAIL is active, then fast
transfer is not allowed.
If busbar voltage falls below
Res voltage limit setting, U_BB_U_RES output is
activated. This allows transfer based on residual voltage transfer.
Control functions
1MRS759142 F
1766
REX640
Technical Manual